If I send eSignature to Yahoo email, it is not showing up on Inbox

[aultabulta]

• I have sent the eSignature invite to xyz@Yahoo.com
• but the email was not received at xyz@yahoo.com's inbox
• When Yahoo end user try to open Google Account using xyz@yahoo.com it is redirecting to his or her another personal email xyz@gmail.com, with the help phone number otp.
• Then they can able to see the eSignature document on Google Drive (under xyz@gmail.com)
• Then an external customer completed the eSignature on that document and submitted.
• Now the CX got the response that "xyz@yahoo.com signed the document" (but technically the document was signed under xyz@gmail.com account)
• this is too complicated to send eSignature to non-google users
  @ProfesorItalo @icrew